Can a builder start additional work without asking me first?

A builder can physically start extra work without your go-ahead, but that doesn't create an obligation for you to pay for it. You only owe money for what you agreed to. If a builder does more than you asked — or something different from what you agreed — without your consent, you generally don't have to pay anything extra, and you can even ask them to undo it at their own cost. The one exception is if your original contract specifically said certain situations might require additional work at extra cost.

Your options when unapproved extra work has been done

Why "we found a problem" isn't automatic consent

Builders sometimes uncover genuine issues mid-job — rot behind a wall, outdated wiring, a structural problem — and it's fair for them to flag it. But flagging a problem and unilaterally deciding to fix it (and bill you) are two different things. You're entitled to:

• Ask for a written quote for the additional work before agreeing to anything
• Take time to consider it rather than deciding on the spot
• Get a second opinion or additional quotes, especially for costly additions
• Say no, and have the situation left as it was (where safely possible) or addressed by someone else

A builder pressuring you to agree immediately, or proceeding without your written agreement, is a red flag worth taking seriously — especially before large sums are involved.

What to check in your original contract

Before refusing to pay, look for any clause stating that in certain circumstances the builder may need to do additional work, with the cost increasing accordingly. If this kind of clause exists and genuinely covers the situation that arose, it can make you liable for the extra cost. If there's no such statement, you're on firmer ground insisting you don't owe anything.

What to do if you're billed for work you didn't approve

1. Check your original paperwork for any clause covering contingent extra work.
2. If none exists, tell the builder in writing that you didn't agree to the additional work and won't be paying for it.
3. Decide whether you want the extra work undone or are happy to keep it — either way, state clearly that you're not paying extra.
4. If they refuse to remove equipment (like scaffolding) related to the disputed extra work, put a clear deadline in writing for its removal.
5. If the dispute doesn't resolve, small claims court handles amounts up to £10,000 in England and Wales (£3,000 in Scotland and Northern Ireland).

Related questions

• Can a builder charge me more than the agreed quote?
• Can I refuse to pay the final invoice if the work is unfinished?
• Who pays if a plumber damages my house?

Official sources

• Citizens Advice — Problem with building work, decorating or home improvements
• Consumer Rights Act 2015